In the framework of rare event searches, the identification of radioactive contaminants in ultra-pure samples is a challenging task, because the signal is often at the same level of the instrumental background. This is a rather common situation for α-spectrometers and other detectors used for low-activity measurements. In order to obtain the target sensitivity without extending the data taking live-time, analysis strategies that highlight the presence of the signal sought should be developed. In this paper, we show how to improve the contaminant tagging capability relying on the time-correlation of radioactive decay sequences. We validate the proposed technique by measuring the impurity level of both contaminated and ultra-pure copper samples, demonstrating the potential of this analysis tool in disentangling different background sources and providing an effective way to mitigate their impact in rare event searches.
@article{arxiv.2105.03140,
title = {Improving radioactive contaminant identification through the analysis of delayed coincidences with an $\alpha$-spectrometer},
author = {G. Baccolo and A. Barresi and M. Beretta and D. Chiesa and M. Nastasi and L. Pagnanini and S. Pozzi and E. Previtali and M. Sisti and G. Terragni},
journal= {arXiv preprint arXiv:2105.03140},
year = {2021}
}